The Internet is a worldwide network of computers linked together by various hardware communication links all running a standard suite of protocols known as TCP/IP (transmission control protocol/Internet protocol). The growth of the Internet over the last several years has been explosive, fueled in the most part by the widespread use of software tools (known as “browsers”) which allow both HTML (hypertext markup language) viewing and HTTP (hypertext transfer protocol) navigation (known as “browsers”). Browsers allow a simple GUI (graphical user interface) to be used to communicate over the Internet. Browsers generally reside on the computer used to access content on the Internet, i.e. the client computer. HTTP is a component on top of TCP/IP and provides users access to documents of various formats using the standard page description language known as HTML and more recently XML (extensible markup language) and XHTML (extensible hypertext markup language), a reformulation of HTML into XML. The collection of servers on the Internet using HTML/HTTP has become known as the “World Wide Web” or simply the “Web.”
Through HTML, XHTML, and interactive programming protocols, the author of content is able to make the content available to others by placing the content, in the form of a Web page, on an Internet Web server. The network path to the server is identified by a URL (Uniform Resource Locator) and, generally, any client running a Web browser can access the Web server by using the URL. A client computer running a browser can request a display of a Web page stored on a Web server by issuing a URL request through the Internet to the Web in a known manner.
Since the Web utilizes standard protocols and a standard rendering engine, i.e. the rendering engine of the browser, the Web has become ubiquitous. One of the primary applications of the Web has been distribution of content in the form of documents. A “document”, as the term is used herein, is any unit of information subject to distribution or transfer, including but not limited to correspondence, books, magazines, journals, newspapers, other papers, software, photographs and other images, audio and video clips, and other multimedia presentations. A document may be embodied in printed form on paper, as digital data on a storage medium, or in any other known manner on a variety of media.
However, one of the most important issues impeding the widespread distribution of digital documents, i.e. documents in forms readable by computers, via electronic means, and the Internet in particular, is the current lack of protection of the intellectual property rights of content owners during the distribution and use of those digital documents. Efforts to resolve this problem have been termed “Intellectual Property Rights Management” (“IPRM”), “Digital Property Rights Management” (“DPRM”), “Intellectual Property Management” (“IPM”), “Rights Management” (“RM”), and “Electronic Copyright Management” (“ECM”), collectively referred to as “Digital rights management (DRM)” herein. There are a number of issues in rights management module: authentication, authorization, accounting, payment and financial clearing, rights specification, rights verification, rights enforcement, and document protection for example.
In the world of printed documents, a work created by an author is usually provided, to a publisher, which formats and prints numerous copies of the work. The copies are then sent by a distributor to bookstores or other retail outlets, from which the copies are purchased by end users. While the low quality of copying and the high cost of distributing printed material have served as deterrents to unauthorized copying of most printed documents, it is far too easy to copy, modify, and redistribute unprotected digital documents. Accordingly, some method of protecting digital documents is necessary to make it more difficult to copy them without authorization.
Unfortunately, it has been widely recognized that it is difficult to prevent, or even deter people from making unauthorized distributions of electronic documents within current general-purpose computing and communications systems such as personal computers, workstations, and other devices connected over communications networks, such as local area networks (LANs), intranets, and the Internet. Many attempts to provide hardware-based solutions to prevent unauthorized copying have proven to be unsuccessful. The proliferation of “broadband” communications technologies and the development of what is presently know as the “National Information Infrastructure” (NII) will render it even more convenient to distribute large documents electronically, including video files such as full length motion pictures, and thus will remove any remaining deterrents to unauthorized distribution of documents. Accordingly, DRM technologies are becoming very useful.
Two basic schemes have been employed to attempt to solve the document protection problem: secure containers and trusted systems. A “secure container” (or simply an encrypted document) offers a way to keep document contents encrypted until a set of authorization conditions are met and some copyright terms are honored (e.g., payment for use). After the various conditions and terms are verified with the document provider, the document is released to the user in clear form. Commercial products such as IBM's Cryptolopes and InterTrust's Digiboxes fall into this category. Clearly, the secure container approach provides a solution to protecting the document during delivery over insecure channels, but does not provide any mechanism to prevent legitimate users from obtaining the clear document and then using and redistributing it in violation of content owners' intellectual property.
Cryptographic mechanisms are typically used to encrypt (or “encipher”) documents that are then distributed and stored publicly, and ultimately privately deciphered by authorized users. This provides a basic form of protection during document delivery from a document distributor to an intended user over a public network, as well as during document storage on an insecure medium.
In the “trusted system” approach, the entire system is responsible for preventing unauthorized use and distribution of the document. Building a trusted system usually entails introducing new hardware such as a secure processor, secure storage and secure rendering devices. This also requires that all software applications that run on trusted systems be certified to be trusted. While building tamper-proof trusted systems is still a real challenge to existing technologies, current market trends suggest that open and untrusted systems such as PC's and workstations using browsers to access the Web, will be the dominant systems used to access copyrighted documents. In this sense, existing computing environments such as PC's and workstations equipped with popular operating systems (e.g., Windows™, Linux™, and UNIX) and render applications such as browsers are not trusted systems and cannot be made trusted without significantly altering their architectures. Of course, alteration of the architecture defeats a primary purpose of the Web, i.e. flexibility and compatibility.
U.S. Pat. No. 5,715,403, the disclosure of which is incorporated herein by reference, discloses a system for controlling the distribution of digital documents. Each rendering device has a repository associated therewith. A predetermined set of usage transaction steps define a protocol used by the repositories for carrying out usage rights associated with a document. However, the use of repositories renders application of the system to distributed networks, such as the Internet, difficult without assuming that the repositories are physically secure and behave in a trusted manner (which may require use of proprietary rendering engine to enforce usage rights associated with documents).
Accordingly, two basic approaches have been taken to control the distribution of documents over the Web. The first approach is the use of subscription based services in which the user is only granted access to content after paying a subscription fee. However, once the subscription fee is paid and the document is rendered by the browser, the user can copy, print, and modify the document, i.e. all control of the document by the publisher is lost.
The second approach is to utilize proprietary formats wherein the document can only be rendered by a select rendering engine that is obligated to enforce the publisher's rights. Of course, this approach requires the use of a single proprietary format and loses the ability to combine plural popular formats and the richness of content associated therewith. Further, this approach requires the user to use a previously unknown rendering application and requires development of the rendering application for each format to be rendered in a secure manner. Further, the documents must be generated or converted using non-standard tools.
Further, there are various known mechanisms by which functionality can be added to a standard rendering engine, such as a Web browser. For example, an ActiveX control can be automatically downloaded and executed by a Web browser. ActiveX is a set of rules for how applications should share information and ActiveX controls can be developed in a variety of programming languages, including C, C++, Visual Basic, and Java.
An ActiveX control is similar to a Java applet. Unlike Java applets, however, ActiveX controls have full access to the Windows™ operating system. Microsoft™ has developed a registration system so that browsers can identify and authenticate an ActiveX control before downloading it run on all platforms, whereas ActiveX controls are currently limited to Windows environments.
A scripting language called VBScript enables Web authors to embed interactive elements in HTML documents to initiate a download and installation of ActiveX controls and other functions. Currently, Microsoft's Web browser, Internet Explorer™, supports Java, JavaScript, and ActiveX, whereas Netscape's Navigator™ browser supports only Java and JavaScript, though its plug-ins can enable support of VBScript and ActiveX.
VYOU.COM has developed a system for protecting intellectual property in documents distributed over the Web. The system includes a software plug-in, to the user's Web browser. The plug-in includes a rendering engine for the proprietary format in which documents are represented and transmitted. Accordingly, documents must be reformatted into the proprietary format and the plug-in rendering engine for the appropriate final viewing format is used in place of the standard browser rendering engine. This arrangement requires the rendering engine for each format must be developed. Therefore, this system is difficult to implement and loses the advantages of the Web as an open architecture.
The proliferation of the Web, and its usefulness in document distribution, makes it desirable to apply DRM features to Web browsers and other standard rendering engines without requiring the rendering engines to be rewritten. However, conventional DRM technologies are not easily adapted to use with Web browsers and other standard rendering engines because they require proprietary formats and rendering engines which contradict the open architecture of the Web. The inability to control application programs, such as Web browsers, independently from their rendering engines has made it difficult to apply DRM features over distribution networks.